Simplified calculation method for negative friction on piles in soft soil foundation

Calculation of negative friction is one of the most important problems in the design of pile foundation engineering.As ports and other ancillary works engineering mostly locate at the region of tideland and dredger fill sedimentation,soft soil layers such as sludge or mud soil which are thick and unconsolidated are widespread.Thus,it's necessary to take into account the influence of negative friction and drop-down loads on pile foundations.At present,although calculation methods of negative friction on pile foundations are provided in the national codes,but relative clauses need to be improved.Based on research results and engineering practice over the world,this paper summarizes the research progress in the negative friction of pile foundation.Furthermore,a simplified method for calculating the negative friction and drop-down loads is provided.Project optimization measures for reducing the friction on pile foundations are discussed and future research are forecasted.